Bulk Explosives

BULK EXPLOSIVES

Container Volumetric Measurement: 

Once the dimensions are known for a particular container, a spreadsheet can easily be set up to assist in the volumetric calculation process.  Please, refer to geometric calculations, or the following web sites for assistance:

Mississippi State UniversityAgricultural & Biological Engineering

http://www.msstate.edu/

There are many shapes that you can enter to calculate volumes for round, rectangular, cones, or other shapes that are encountered.  The calculations found at this location are “unit free” which means you keep the same units for each measurement and you get the result in cubed “units”.  For the total weight you just need to convert your product density to the cubed unit factor (i.e., convert g/cc to Lbs/Cu Ft) and multiply time the resultant volume from the total of all cubed “unit” results for the container.  NOTE:  you may have to do several calculations to determine the volume contained inside the container.

Gravity Wagons (should look familiar):

Round Bins (listed as a partially filled grain bin) and round based cones (Multi-part calculation for an emulsion bin):

Rectangular Bins with Pyramidal Base (two part calculation for an overhead ANFO bin):
   

o Trapezoidal Tank (partially filled):
 

o Cylinder - Partially Filled - Laying Down:
 

o Oval Tank - Partially Filled  (listed as a Milk Tank):
 

Inclined Cylinders and other volumetric calculation done on line after you “register” at this website:

http://www.lmnoeng.com/Volume/InclinedCyl.htm
 

Here is another diagram for the volume for a manure spreader found in another paper from the University of Missouri;  However, volumetric calculations are utilized for a variety of products.  And this particular paper does a good job of explaining one particular calibration process.

http://muextension.missouri.edu/xplor/envqual/wq0213.htm

 
Common Volumetric Mathematical Formula, where:
A = Angle
C = Circumference
D = Diameter
H = Height
L = Length
Pi = 3.141592654
R = Radius
W = Width


STRUCTURE FORMULA

Rectangular Box  L X W X H
Right Prism [0.5 X (W X H)] X L  - or -  (Area of Base) X L

Right Pyramid  Pointed End:  (1/3) X (W X L) X H – or -  (1/3) X (Area of Base) X H

or Flat Ended:  XXXXXXXXXXXXX
      

Circumference Pi X 2 X R - or -  Pi X D
  

Radius C / (2 X Pi)
Cylinder Pi X (R^2) X H

Right Cone Pointed End: (1/3) X (Pi X R^2 X H)

or  Flattened End:  {Pi X [(R #1^2)+(R#1*R#2)+(R#2^2)] X H}/3

Unlevel Right Cylinder

or Frustum of a Right Cylinder Volume = [Pi X R^2 X (Height #1 + Height #2)] / 2   

Truck Bin Volume =

[H(t) X W(t) X L] + [H(b) X W(b) X L] + {[W(t) - W(b)] X H(b) X L}
       

Measurement Method Consistency:  The variation from different methods, methods of measurement, etc. needs to be eliminated to maintain consistency.  The best method may change with the product (AN, ANFO, Emulsion, Blend, etc.), container, or location ( the level of the equipment in the mine bench area vs the scale area should be considered for maintaining a consistent or non-angular level product level).

Container Volume:  Each bulk container will have a different volume as all bins are not exactly the same.  Measurements should be made and verified from time to time.  Surface area is critical and measurement of the irregular surface area is essential.  Angular measurements are also essential for the initial set up.  Volume of container may change with external influences such as age (metal fatigue), expansion and contraction due to temperature changes, patching, etc.

Material behaviour
Angle of repose:  The angle of repose varies with different products and environmental conditions.  Because of this a natual angle of repose can not be assumed but rather measured for each volumetric calculation.

Prilled product such as ANFO, the angle of repose is not constant because the amount of fines will increase the angle of repose (near vertical angles maybe observed in product with excessive fines).

Fluid products such as Emulsion, the angle of repose is a variable depending on the chemistry and environmental factors. 

CHEMISTRY: The type and amount of the fuel phase of the manufacturing process may introduce materials with variable consistencies that will affect the fluidic flow of diesel fuel to stiffness of wax. 

ENVIRONMENT: The environmental factors such as temperature and humidity may introduce variables to the angle of repose that varies greatly with the type of fuel and the percentage of water in the product.  Generally colder temperatures create “stiffer” or higher angles of repose.
Blended products generally have a much higher angle of repose than either of the liquid or prilled products alone.  The percent blend and the environmental factors vary.

Bridging:  Bridging creates voids within the product to be measured and must be eliminated when making volumetric calculating.   Utilization of bin vibrators, impacting the container with rubber mallets, or the use of non-sparking poles to free up the bridged area are necessary prior to any measurement for the volume.  Anything that has the potential for creating voids will change volumes.

Surface Area (Vortex effect):  Once a bin has been filled and material flows thru the bottom an indention occurs on the surface area creating a vortex or sunken center of the surface area does affect the volumetric calculation.  Measurement should take the vortex into affect.

Prilled products are usually in a rectangular bin.  Measurements must include the surface area which might include measurements to the edges on all four sides and in the center of the vortex area.

Fluid products are usually stored in round containers.  Often fluid products will return to an almost negligible vortexed surface area over time (depending on the rigidity of the product and/or environmental factors; i.e., temperature).  When the vortex area is of sufficient volume the measurements must document the location of the vortex and the height distance variations.  An inverted cone calculation may be utilized to calculate the missing material.

Caking
Lumps:  Lumps must be broken up to assist in proper flow of material.  Grates or screens placed at the point of transfer assist in reducing or diminishing the transference of lumps (particularly with AN prill).

Sticking to container sides and top:  Proper “house keeping” or physical maintenance of the products in the containers is the key here.  Clean or scrape down containers prior to delivery of fresh product.  Material must be removed from the sides and/or the top of the container to capture the total volume of product.  Non-sparking paddles or squeegee apparatus must be utilized to consolidate the product into a continuous mass.  Hardened layers of AN prill can be seen on the side of containers that are not maintained properly during period of “cycling” or thickened layers of emulsion are found on the side of bins that are not maintained on a regular basis.  When container bins are improperly maintained, lumps form and when the lumps do eventually release, they may become usable and must be destroyed.  Unusable material must be documented, inventory adjusted, and disposed of in an environmentally responsible manner. 

Environmental Effects (temperature, humidity, elevation)
Expansion and contraction:  Density measurements must be conducted and documented prior to conducting volumetric calculations.  Know the response to environmental effects for products being inventoried.  Emulsions generally decrease volume as they cool from manufacture.  Also, be aware that product volume may change as a result of the atmospheric elevation pressure change from the point of manufacture and/or storage to the point of delivery (generally the higher the elevation the larger the volume – and this occurs more for an emulsion type product that it would for a prilled AN type product).

Cycling:  Rotate inventory more during period where environmental conditions are prone to cycling to reduce this effect.  Products containing AN prills are a prime victim when temperature variations shift above and below (~93„a F).

Handling:  Document the delivered amounts and account for lost material (caking, leakage, spills) during processing and loading

AN handling creates fines and can increase bulk density:  Document the product height of pre and post transport for containers where volumetric calculations will be utilized.  The affect of transporting a product may have a significant affect on the particle density for various products thru an effect referred to as “packing” which happens as the particles vibrate during the normal transport.  This affect also will result in errors in the volumetric calculations because of the increased density of the product.


Emulsion handling can reduce voids and increase density:  Reduce transference of products to a minimum. 

Emulsion handling can decrease density by entraining air:  Reduce transference of products to a minimum.

Errors in mixing percentages:  Periodic volumetric calibrations of pumps, augers, and the speeds at which these devices operate will assist in proper mixing percentages.  Documentation of the material flow rate and device rotational volumes assists in the determination of the mixing percentage.  This is essential in the determination of the density of blended products.  Document margins of error.

Variation in raw material density:  Document product density prior to any volumetric calculations.

Aging increases density:  Order and inventory product so that aging does not become a factor.